Water Quality in the Super-intensive Shrimp Ponds in Bac Lieu Province, Vietnam

The study was conducted to assess the water quality in super-intensive shrimp ponds in Bac Lieu using water quality parameters such as pH, biochemical oxygen demand (BOD5), and chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), ammonium (NH4+-N), residual chlorine, total oil and grease and total coliform. Sixty water samples in super-intensive shrimp ponds were collected in 2019 Bac Lieu province. The results showed that the nutrients in the water samples include TN (0.54-36.12 mg/l), NH4+-N (0.016-1,246 mg/l) and TP (0.34-6.12 mg/l) did not exceed the limits of QCVN 40: 2011/BTNMT (column B). Residual chlorine (less than 0.5 mg/l), total oil and grease (<0.2 mg/l) and water pH (5.5-9.0) have not affected the water environment and the growth of shrimp. In water samples there were biodegradable organic substances (BOD5/COD = 0.53> 0.4), BOD (4.43-55.19 mg/l) and TSS (6.1-320 mg/l) exceeding the limits of QCVN 40: 2011/BTNMT (column B) at some locations, while COD (10,21-90,12 mg/l) was below limit of QCVN 40: 2011/BTNMT (column B). Water in shrimp ponds is contaminated with microorganisms when the total coliform density ranged from 1,300 to 95,000 MPN/100ml and there were 40/60 locations having coliform density greater than 5,000 MPN/100ml. The current findings provide important information for shrimp pond management.